1. Field of Invention
This invention relates to an outboard boat engine air intake device. More particularly, this invention relates to an air intake device that easily attaches to a boat engine.
2. Description of Related Art
Many outboard boat motors include a multi-cylinder engine in which the crank shaft is vertically oriented. Recently, fuel injection air intake devices have become widely used in engines of this type.
Fuel injection air intake devices used in vertically oriented multi-cylinder engines include a surge tank that regulates the air flow, as well as air intake pipes that extend substantially horizontally in multiple vertical stages from the surge tank to the respective intake ports of the engine and fuel injectors that inject fuel into the intake ports. Also, the surge tank has a throttle valve that regulates the amount of air that is taken in.
When the throttle valve opens, fresh air flows into the surge tank, through the various air intake pipes, and into the intake ports. Fuel injected by the injectors near the intake ports flows into and is mixed with the fresh air to create a combustible gaseous mixture taken into the engine. A breather pipe extends from the engine cylinder head and is connected to the throttle valve.
The surge tank, the air intake pipes, and the intake manifold cover forming the air intake device are generally cast from a lightweight and durable material such as an aluminum alloy. The surge tank is then firmly bolted to the engine crank case, and the intake manifold cover is firmly bolted to the cylinder head of the engine with the air intake pipes supported between the surge tank and the intake manifold cover.
Although the surge tank, the air intake pipes, and the intake manifold cover are formed as a single unit, the engine includes multiple parts, such as a crank case, a cylinder block, and a cylinder head, that must be assembled. Therefore, misalignment between the air intake device and the engine is common, causing difficulty in connecting the various air intake components to the engine. Conventionally, to avoid such conditions, the components must be manufactured and assembled with great precision, thus significantly increasing the costs associated with the devices.
Another problem associated with conventional air intake devices arises because of the complexity of manufacturing the surge tank, air intake pipes, and intake manifold cover as a single, large unit.
Thus, an outboard boat engine air intake device is needed that can be easily attached to an engine, and that further can be manufactured with less complexity than conventional devices.